Engine Noise Diagnosis?

[NashBronco]

Can anyone “diagnose” this engine noise that happens when I come off throttle?

Also, I can’t turn my distributor any further clockwise. Can I just pick it up and “restab” it?

https://youtu.be/UhWRb2z1BnQ

 

[Broncobowsher]

I can rarely figure noises on internet videos.

But yes, you can restab the distributor a tooth over. Getting it to mate with the oil pump driveshaft can be a pain. Many times put a socket on a long extension and clock the oil pump drive a little, don't drop the socket. Or jump a tooth and bump the engine over to align the drive to the pump.

Or even easier, just move all the plug wires over one hole. Move the wires clockwise one hole then turn the distributor counterclockwise one holes width.

 

[Slowleak]

Easiest way to get the distributor back in line is to move all your wires clockwise in the cap. Then turn the distributor counterclockwise.

 

[NashBronco]

I agree. It’s really hard to diagnose something from a video... it worth a shot. I assume it is a piston knocking around. I assume an exhaust leak would be more constant? Also it’s more of a knock than a tick which leads me to piston.

I’ll try that with the distributor tomorrow. Never knew that trick.

 

[ugly74]

Hard to say, but it sure sounds like a bottom end noise. Run it till it lets go, and then you’ll know

 

[DirtDonk]

I have not listened to the video yet, but one thing you can do with knocking I've found, is remove or tighten the V-belts driving the front accessories.
I was listening to a real death-knock in a '69 here a few years ago, and sentenced it to an early death. The guy took it to a shop the next day and tightened a belt and the noise went away!
I kid you not, I still don't know what was causing it. Maybe it was truly an inner bearing knock and the extra tension of the fan belts put just enough English on the crank to temporarily stop the noise.
But it's been a couple of years now and no more reports of knocking.

So at least give it a try. Much easier (and cheaper) than rebuilding an engine!

Good luck.

Paul

 

[DirtDonk]

Well I just watched the vid and in your case it sounds funky through the carburetor too. Or at least sounds it from here. What do you think about that from your vantage point?

It had a lot more subtleties to it than just a knock. Lots of peripheral accompaniment that did not add to my confidence in the fan-belt fix.
But still worth a shot!

Paul

 

[B RON CO]

Hi, X2 on slowleak for an easy way to re orient the vacuum canister.
Next, as mentioned, run it with the belts off.
A compression test and vacuum gauge gives a lot of information about your engine.
Good luck